Recent years have seen an upsurge in the popularity of fixed tone whistles. In the usual case, two or more sound chambers of different lengths are connected to a common mouthpiece. When a person blows through the mouthpiece, two or more different pitches, each proportional to the length of its associated sound chamber, are generated. These pitches, taken together, provide a sound of a particular perceived quality which is the tone of the whistle. Because this tone cannot be varied because the pitches of the sounds generated in the various chambers cannot be changed, the whistle tone is fixed.
In a number of cases, the chambers are so designed so that the pitches are dissonant and at frequencies such that a fairly rapid "beat" arises as the frequencies alternately reinforce and negate each other. In some cases, the chamber design is so chosen to provide three pitches whose "beat" approximates the oscillation of a mechanical armature such as a cork ball in a typical whistle. Two such constructions are known in the prior art and each employs three chambers, each of a different length. These constructions eliminate the need for such an armature as well as the problems that may accompany the use of a whistle with an armature, such as freeze up in cold weather.
While successful to this degree, fixed tone whistles are not without their disadvantages. For one, the dissonance produced by the different pitches may be overly unpleasing to certain listeners. Secondly, the "beat" cannot be altered as it is a function of chamber fabrication.
Thirdly, because the pitch difference is typically based on a difference in length in the chambers, fixed tone whistles frequently are relatively long and may be unwieldy in comparison to the conventional armature equipped whistle commonly employed in athletic contests today.
Furthermore, such whistles may be difficult to fabricate, requiring complex molding techniques or the use of assembly techniques that include the installation of a partition in a barrel, an insert or the like coupled with a need to mount and seal various components or else the desired tonal effect may not be achieved.
The present invention is directed to overcoming one or more of the above problems.